Research from an 18-year long survey of thousands of households, published earlier this week, points to the relative stability of marriage compared with cohabitation, especially for any children involved. Rather than me try to summarise it, here's a chunk from this report on the research:
John Ermisch, a Professor of Economics at the University of Essex who analysed the data, said: "The rise in births outside marriage is a real cause for concern.
"It is primarily attributable to the increase in people's tendency to cohabit in their first partnership and to have children within these unions. The instability of these unions means, however, than more British children will spend significant parts of their childhood in families with only one parent - and this appears to have long-term negative consequences."
The new report, published by the university's Institute for Social & Economic Research to commemorate 18 years of the British Household Panel Survey, shows that just 9 per cent of births in Britain were outside wedlock in 1975. By 2006, however, this figure had risen to 44 per cent. Three-quarters of these were jointly registered by both parents, suggesting they were living together.
But Prof Ermisch said that many of these cohabiting relationships are doomed to failure, leaving the baby in a single-parent family.
"The time couples spend living together in cohabiting unions before either marrying each other or separating is usually very short, the median duration being about two years.
"The unions that produce children are much less likely to be converted into marriage and more likely to break up than childless ones."
He said only 35 per cent of cohabiting couples stay together until their children turn 16, compared with 70 per cent of married couples. "Having a child in a cohabiting union is often not indicative of a long-term partnership." In addition, single mothers take much longer to find another partner, which leaves their children growing up without a father figure.
Those born into a single-mother household spend 7.8 years of their first 16 years without a second parent, the figures show. Children born to couples living together spend on average 4.7 years with just one parent, but those born to married parents spend on average all but 1.6 years of their childhood with two parents.
Prof Ermisch went on: "Analysis of people born in the 1970s using the BHPS data indicates that a child who experiences a period in a one-parent family, particularly before they start school, ends up with lower grades, worse job prospects and in poorer health than a child from a family that remains intact."
Certain ministers say that family arrangements are a lifestyle choice, and not for the government to promote or encourage. Conservative thinking is slightly more joined up (see p11 of this paper from the Tories 'Childhood Review') An alternative view is here. One challenge of this is to have the debate without the cries that this is stigmatising single parents.